I have never had an issue with allergies, but at 23 i am having symptoms: congestion, itchy eyes, sneezing. it has lasted 2-3 weeks. will it go away?

Think environment: Recently moved? New pet? New roommate? Recently married? New job? Do a complete inventory. What has changed? Go back at least one year. For example: you might have moved 10 months ago, but only recently began being exposed to a pollen you to which you are allergic.

Probably: This certainly sounds like an allergic reaction to something and unless you are continuing to be exposed, it should improve. Are there new things in your enviroment: pets, furniture, job, etc. Have you recently relocated to the area? If it is due to the unusually high pollen levels it should improve as the weather (and pollens) change.